Zhou Bin, 41, is seeking legal assistance over possible bribery and other charges, according to three people familiar with the case who declined to be named.

Zhou Bin is allegedly involved in illegal dealings in Sichuan and the oil industry.

He has been formally detained since December.

His detention is a crucial step towards launching judicial proceedings against Zhou, and possibly also his father, who would become the highest-ranking party leader in decades to be embroiled in a graft scandal.